| 摘要 |
<p>Surge control systems prevent and control a surge condition for fixed or variable speed compressors and compressors having variable geometry which provide air to pneumatic loads. A signal proportional to the ratio of the measured compressor outlet pressure to the measured inlet pressure is compared with a signal corresponding to a selected reference pressure to provide a vent valve command signal. When the signal representing the ratio of the measured pressure exceeds the signal corresponding to the selected reference pressure, a surge condition is developing and the vent valve command signal causes a valve to vent a portion of the air to the pneumatic load. The venting of the air reduces the measured pressure ratio and the vent valve command signal decreases, to close the valve. A signal is provided to reduce the effect of the reference pressure ratio if the weight flow rate through the compressor is reduced, as by decreasing compressor speed and/or repositioning the inlet guide vanes of the compressor.</p> |
